Text Detection with YOLO on Challenging Images

I have images that look as follows:

My goal is to detect and recognize the number 31197394. I have already fine-tuned a deep neural network on text recognition. It can successfully identify the correct number, if it is provided it in the following format:

The only task that remains is the detection of the corresponding bounding box. For this purpose, I have tried darknet. Unfortunately, it's not recognizing anything. Does anyone have an idea of a network that performs better on these kind of images? I know, that amazon recognition is able to solve this task. But I need a solution that works offline. So my hopes are still high that there exist pre-trained networks that work. Thank's a lot for your help!

Thanks for your answers guys! You were right, I had to finetune yolo to make it work. So I created a dataset and fine-tuned yolov5. I am surprised how good the results are. Despite only having about 300 images in total, I get an accuracy of 97% to predict the correct number. This is mainly due to strong augmentations. And indeed the memory requirements are large, but I could train on a 32 GM RAM machine. I can really encourage anyone who faces similar problems to give yolo a shot!!